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Li WB, Huber GM, Blok HP, Gaskell D, Horn T, Semenov-Tian-Shansky K, Pire B, Szymanowski L, Laget JM, Aniol K, Arrington J, Beise EJ, Boeglin W, Brash EJ, Breuer H, Chang CC, Christy ME, Ent R, Gibson EF, Holt RJ, Jin S, Jones MK, Keppel CE, Kim W, King PM, Kovaltchouk V, Liu J, Lolos GJ, Mack DJ, Margaziotis DJ, Markowitz P, Matsumura A, Meekins D, Miyoshi T, Mkrtchyan H, Niculescu I, Okayasu Y, Pentchev L, Perdrisat C, Potterveld D, Punjabi V, Reimer PE, Reinhold J, Roche J, Roos PG, Sarty A, Smith GR, Tadevosyan V, Tang LG, Tvaskis V, Volmer J, Vulcan W, Warren G, Wood SA, Xu C, Zheng X. Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction. Phys Rev Lett 2019; 123:182501. [PMID: 31763910 DOI: 10.1103/physrevlett.123.182501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/01/2019] [Indexed: 06/10/2023]
Abstract
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e^{'}pω, at central Q^{2} values of 1.60, 2.45 GeV^{2}, at W=2.21 GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45 GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.
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Affiliation(s)
- W B Li
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- College of William and Mary, Williamsburg, Virginia 23185, USA
| | - G M Huber
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - H P Blok
- VU University, NL-1081 HV Amsterdam, Netherlands
- NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, Netherlands
| | - D Gaskell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Horn
- Catholic University of America, Washington, D.C. 20064, USA
| | - K Semenov-Tian-Shansky
- National Research Centre Kurchatov Institute: Petersburg Nuclear Physics Institute, RU-188300 Gatchina, Russia
- Saint Petersburg National Research Academic University of the Russian Academy of Sciences, RU-194021 St. Petersburg, Russia
| | - B Pire
- CPHT, CNRS, École Polytechnique, IP Paris, 91128-Palaiseau, France
| | - L Szymanowski
- National Centre for Nuclear Research (NCBJ), 02-093 Warsaw, Poland
| | - J-M Laget
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - K Aniol
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - J Arrington
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - E J Beise
- University of Maryland, College Park, Maryland 20742, USA
| | - W Boeglin
- Florida International University, Miami, Florida 33119, USA
| | - E J Brash
- Christopher Newport University, Newport News, Virginia 23606, USA
| | - H Breuer
- University of Maryland, College Park, Maryland 20742, USA
| | - C C Chang
- University of Maryland, College Park, Maryland 20742, USA
| | - M E Christy
- Hampton University, Hampton, Virginia 23668, USA
| | - R Ent
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E F Gibson
- California State University, Sacramento, California 95819, USA
| | - R J Holt
- Caltech, Pasadena, California 91125, USA
| | - S Jin
- Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - M K Jones
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C E Keppel
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Hampton University, Hampton, Virginia 23668, USA
| | - W Kim
- Kyungpook National University, Daegu, 702-701, Republic of Korea
| | - P M King
- Ohio University, Athens, Ohio 45701, USA
| | - V Kovaltchouk
- Ontario Tech University, Oshawa, Ontario L1G 0C5, Canada
| | - J Liu
- Shanghai Jiao Tong University, Shanghai 200240, China
| | - G J Lolos
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - D J Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D J Margaziotis
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33119, USA
| | - A Matsumura
- Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - D Meekins
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Miyoshi
- Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - H Mkrtchyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - I Niculescu
- James Madison University, Harrisonburg, Virginia 22807, USA
| | - Y Okayasu
- Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - L Pentchev
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Perdrisat
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - D Potterveld
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - V Punjabi
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - P E Reimer
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33119, USA
| | - J Roche
- Ohio University, Athens, Ohio 45701, USA
| | - P G Roos
- University of Maryland, College Park, Maryland 20742, USA
| | - A Sarty
- Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
| | - G R Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - V Tadevosyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - L G Tang
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
- Hampton University, Hampton, Virginia 23668, USA
| | - V Tvaskis
- NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, Netherlands
- VU University, NL-1081 HV Amsterdam, Netherlands
| | - J Volmer
- VU University, NL-1081 HV Amsterdam, Netherlands
- DESY, Hamburg 22607, Germany
| | - W Vulcan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - G Warren
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | - S A Wood
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Xu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - X Zheng
- University of Virginia, Charlottesville, Virginia 22904, USA
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Huber GM, Blok HP, Butuceanu C, Gaskell D, Horn T, Mack DJ, Abbott D, Aniol K, Anklin H, Armstrong C, Arrington J, Assamagan K, Avery S, Baker OK, Barrett B, Beise EJ, Bochna C, Boeglin W, Brash EJ, Breuer H, Chang CC, Chant N, Christy ME, Dunne J, Eden T, Ent R, Fenker H, Gibson EF, Gilman R, Gustafsson K, Hinton W, Holt RJ, Jackson H, Jin S, Jones MK, Keppel CE, Kim PH, Kim W, King PM, Klein A, Koltenuk D, Kovaltchouk V, Liang M, Liu J, Lolos GJ, Lung A, Margaziotis DJ, Markowitz P, Matsumura A, McKee D, Meekins D, Mitchell J, Miyoshi T, Mkrtchyan H, Mueller B, Niculescu G, Niculescu I, Okayasu Y, Pentchev L, Perdrisat C, Pitz D, Potterveld D, Punjabi V, Qin LM, Reimer PE, Reinhold J, Roche J, Roos PG, Sarty A, Shin IK, Smith GR, Stepanyan S, Tang LG, Tadevosyan V, Tvaskis V, van der Meer RLJ, Vansyoc K, Van Westrum D, Vidakovic S, Volmer J, Vulcan W, Warren G, Wood SA, Xu C, Yan C, Zhao WX, Zheng X, Zihlmann B. Separated response function ratios in exclusive, forward π(±) electroproduction. Phys Rev Lett 2014; 112:182501. [PMID: 24856691 DOI: 10.1103/physrevlett.112.182501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Indexed: 06/03/2023]
Abstract
The study of exclusive π(±) electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio RL=σL(π-)/σL(π+) is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of RT=σT(π-)/σT(π+) from unity at small -t, to 1/4 at large -t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to perturbative QCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive π(±) electroproduction on the deuteron at central Q(2) values of 0.6, 1.0, 1.6 GeV(2) at W=1.95 GeV, and Q(2)=2.45 GeV(2) at W=2.22 GeV. Here, we present the L and T cross sections, with emphasis on RL and RT, and compare them with theoretical calculations. Results for the separated ratio RL indicate dominance of the pion-pole diagram at low -t, while results for RT are consistent with a transition between pion knockout and quark knockout mechanisms.
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Affiliation(s)
- G M Huber
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - H P Blok
- VU university, NL-1081 HV Amsterdam, The Netherlands and NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, The Netherlands
| | - C Butuceanu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - D Gaskell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Horn
- Catholic University of America, Washington, DC 20064, USA
| | - D J Mack
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D Abbott
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - K Aniol
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - H Anklin
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Florida International University, Miami, Florida 33119, USA
| | - C Armstrong
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - J Arrington
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K Assamagan
- Hampton University, Hampton, Virginia 23668, USA
| | - S Avery
- Hampton University, Hampton, Virginia 23668, USA
| | - O K Baker
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA
| | - B Barrett
- Saint Mary's University, Halifax, Nova Scotia B3H 3C3 Canada
| | - E J Beise
- University of Maryland, College Park, Maryland 20742, USA
| | - C Bochna
- University of Illinois, Champaign, Illinois 61801, USA
| | - W Boeglin
- Florida International University, Miami, Florida 33119, USA
| | - E J Brash
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - H Breuer
- University of Maryland, College Park, Maryland 20742, USA
| | - C C Chang
- University of Maryland, College Park, Maryland 20742, USA
| | - N Chant
- University of Maryland, College Park, Maryland 20742, USA
| | - M E Christy
- Hampton University, Hampton, Virginia 23668, USA
| | - J Dunne
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - T Eden
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Norfolk State University, Norfolk, Virginia 23504, USA
| | - R Ent
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - H Fenker
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - E F Gibson
- California State University, Sacramento, California 95819, USA
| | - R Gilman
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - K Gustafsson
- University of Maryland, College Park, Maryland 20742, USA
| | - W Hinton
- Hampton University, Hampton, Virginia 23668, USA
| | - R J Holt
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - H Jackson
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S Jin
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - M K Jones
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - C E Keppel
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA
| | - P H Kim
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - W Kim
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - P M King
- University of Maryland, College Park, Maryland 20742, USA
| | - A Klein
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - D Koltenuk
- University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - V Kovaltchouk
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - M Liang
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Liu
- University of Maryland, College Park, Maryland 20742, USA
| | - G J Lolos
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - A Lung
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - D J Margaziotis
- California State University Los Angeles, Los Angeles, California 90032, USA
| | - P Markowitz
- Florida International University, Miami, Florida 33119, USA
| | | | - D McKee
- New Mexico State University, Las Cruces, New Mexico 88003-8001, USA
| | - D Meekins
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - J Mitchell
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | | | - H Mkrtchyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - B Mueller
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - G Niculescu
- James Madison University, Harrisonburg, Virginia 22807, USA
| | - I Niculescu
- James Madison University, Harrisonburg, Virginia 22807, USA
| | | | - L Pentchev
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - C Perdrisat
- College of William and Mary, Williamsburg, Virginia 23187, USA
| | - D Pitz
- DAPNIA/SPhN, CEA/Saclay, F-91191 Gif-sur-Yvette, France
| | - D Potterveld
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - V Punjabi
- Norfolk State University, Norfolk, Virginia 23504, USA
| | - L M Qin
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - P E Reimer
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J Reinhold
- Florida International University, Miami, Florida 33119, USA
| | - J Roche
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - P G Roos
- University of Maryland, College Park, Maryland 20742, USA
| | - A Sarty
- Saint Mary's University, Halifax, Nova Scotia B3H 3C3 Canada
| | - I K Shin
- Kyungpook National University, Daegu 702-701, Republic of Korea
| | - G R Smith
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S Stepanyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - L G Tang
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA
| | - V Tadevosyan
- A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia
| | - V Tvaskis
- VU university, NL-1081 HV Amsterdam, The Netherlands and NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, The Netherlands
| | | | - K Vansyoc
- Old Dominion University, Norfolk, Virginia 23529, USA
| | - D Van Westrum
- University of Colorado, Boulder, Colorado 80309, USA
| | - S Vidakovic
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - J Volmer
- VU university, NL-1081 HV Amsterdam, The Netherlands and DESY, Hamburg, Germany
| | - W Vulcan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - G Warren
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - S A Wood
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - C Xu
- University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - C Yan
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
| | - W-X Zhao
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - X Zheng
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B Zihlmann
- Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and University of Virginia, Charlottesville, Virginia 22901, USA
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Nakamura SN, Matsumura A, Okayasu Y, Seva T, Rodriguez VM, Baturin P, Yuan L, Acha A, Ahmidouch A, Androic D, Asaturyan A, Asaturyan R, Baker OK, Benmokhtar F, Bosted P, Carlini R, Chen C, Christy M, Cole L, Danagoulian S, Daniel A, Dharmawardane V, Egiyan K, Elaasar M, Ent R, Fenker H, Fujii Y, Furic M, Gan L, Gaskell D, Gasparian A, Gibson EF, Gogami T, Gueye P, Han Y, Hashimoto O, Hiyama E, Honda D, Horn T, Hu B, Hungerford EV, Jayalath C, Jones M, Johnston K, Kalantarians N, Kanda H, Kaneta M, Kato F, Kato S, Kawama D, Keppel C, Lan KJ, Luo W, Mack D, Maeda K, Malace S, Margaryan A, Marikyan G, Markowitz P, Maruta T, Maruyama N, Miyoshi T, Mkrtchyan A, Mkrtchyan H, Nagao S, Navasardyan T, Niculescu G, Niculescu MI, Nomura H, Nonaka K, Ohtani A, Oyamada M, Perez N, Petkovic T, Randeniya S, Reinhold J, Roche J, Sato Y, Segbefia EK, Simicevic N, Smith G, Song Y, Sumihama M, Tadevosyan V, Takahashi T, Tang L, Tsukada K, Tvaskis V, Vulcan W, Wells S, Wood SA, Yan C, Zhamkochyan S. Observation of the (Λ)(7)He hypernucleus by the (e, e'K+) reaction. Phys Rev Lett 2013; 110:012502. [PMID: 23383783 DOI: 10.1103/physrevlett.110.012502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Indexed: 06/01/2023]
Abstract
An experiment with a newly developed high-resolution kaon spectrometer and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab. The ground state of a neutron-rich hypernucleus, (Λ)(7)He, was observed for the first time with the (e, e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The (Λ)(7)He binding energy supplies the last missing information of the A = 7, T = 1 hypernuclear isotriplet, providing a new input for the charge symmetry breaking effect of the ΛN potential.
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Affiliation(s)
- S N Nakamura
- Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan
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